Pressure-developing pneumatic tool.



J. L. WAGNER.

E DEVELOPING PNBUMATIO TOOL.

PRESSUR APPLICATION FILED MAR.1,1910v Stream vs,

I Patented Apr. 14, 1914.

n 1m a JOHN I4; W'Aenn Specification of Letters Patent. Application filed March 1, 1910. Serial No. 546,686.

v u g Eismao'usa nnw z" onx, assronon. To THE PNEUMELECTRIG macnrnn company, or SYRACUSE, NEW YORK, A CORPORATION OF NEW YORK.

ranssunn nnvnnornve PNEUMATIC TOOL.

V Patented Apr. 1d, 191%.

T 0 all whom it may concern Be it known that 1, JOHN L. WAGNER, a

citizen of the United States, and resident of Syracuse, in the county of Onondaga and ing force of air-under pressure and particularly to that class of such tools in which the compression of the air is developed by the tool or machine itself through the medium of a'piston that reciprocates in such relation to the tool piston (preferably in the same cylinder therewith) that it not only compresses and then releases a body of air to act expansivelyagainst the tool piston, but it retracts thetool piston during the compress ing stroke, toa position in which it will encounter the force of the expanding body of air to the best advantage.

One object of my present invention is to provide means whereby the air utilized within the machine will be conserved as much as possible and the introduction of new air with its unavoidable dust will be reduced to a minimum.

Another object is to provide means-whereby a portion of the body'of air compressed as stated, may be utilized for the purpose of increasing the pressure on the forward face of the tool piston above that supplied by atmosphere, so that it will respond more readily and more effectively to the suction of the compressing piston during the retracting stroke, and to these ends the invention consists of certain novel features of construction hereinafter fully; described and particularly pointed out in the claims.

In the accompanying drawings: Figure 1' is a vertical longitudinal section of a machine of known type having my present improvements applied thereto, the pistons being in the positions assumed immediately after delivery of the working stroke, the tool piston being driven to the forward limit by the expanding air and the retracting and compressing iston being at the completion of its compressing stroke; Fig. 2 is a view of that portion, of Fig. l with which the invention is immediately concerned,

showing the retracting and compressing piston after commencement of its rearward stroke; F ig. 3 is a View similar to Fig. 2 showing the retracting and compressing piston and the tool piston after the latter has completed its rearward stroke and Fig. 4 is a detailview showing a modified construction of the cylinder. 7

Referring to Fig. 1, 1 represents a suitably housed electric motor connected through any suitable gearing 2, which translates rotary into reciprocating motion, to the rod 3 0f the compressing and retracting piston 4:,

.fitted to reciprocate in the cylinder 5 .in

which is also housed a tool piston 6 adapted to pereussively actuate a tool as for instance through its forwardly projecting rod 7. Piston 4 is constantly reciprocated in the cylinder 5 and in so acting, it expels air through a valved port 8, on its forward stroke, until it reaches its limit in close proximity to the piston 6, then on its rearward movement, it develops a partial vacuum behind the piston 6 so that the latter tends to follow it rearward under atmosphere or other pressureand at the same time the said rearward movement of the piston 4 coinpresses a considerable body of air behind it at the rear end of the cylinder 5, and in a reservoir 9 through port 10, until the pistons 4 and 6 approach their rearward limit of movement, when the highly compressed air in rear of the piston 4 will enter through aport 11, which has then been uncovered by the piston 4 and, expanding, will drive the piston 6 forward to develop the porous-- sive stroke, after which the piston 4 again moves forward, to repeat the cycle of steps. During the forward stroke of the piston 6, air trapped in advance of, it is forced through a port 12 into the reservoir 9 so as to avoid waste and reduce the introduction of new 'air with unavoidable dust and grit. For the same consideration, it is desirable to have the port 8 also discharge into the reservoir 9, It will, of course, be understood that the pressure in advance of the piston 6 is not 100 sufficient to offer material resistance to the Workin stroke until piston 6 approaches its forward limit by which time the stored pressure in reservoir 9 has been so far relieved through the port 11 as to permit port 12 to open and thus avoid material reduction of the efliciency of the stroke.

Some of the features of the machine as thus far described are inventionsof another and are, therefore, not claimed by me except in combination with features of my invention as hereinafter pointed out.

It has heretofore been proposed to open' a communication with atmosphere at the forward end of the cylinder 1, in front of the piston 6 so that atmospheric pressure, on the front face of said piston will act to drive it rearward, when a partial vacuum is created in rear of it by retraction of piston 4. Under some circumstances, atmospheric pressure is not sufficient to satisfactorily retract the piston 6, as for instance, when the machine is used in a vertical position and the weight of the piston, its rod and the attached tool must be overcome in addition to the friction of the moving parts. To render the retraction of the piston 6 more positive, I have provided a feed passage 13 for fluid pressure medium, which leads from a port 14 near the rear end of the cylinder to a port 15 at a point beyond the extreme forward limit of the piston 6. The effect of this feed passage is to deliver to the space in front of the piston 6 some of the air pressure developed during the earlier part of the rearward movement of the iston a and thereby exert a greater retracting pressure on said piston 6 than if merely atmospheric pressure were relied upon, as heretofore. In this manner, the piston 4 is caused to exert upon the piston 6, not only the so called suction but at the same time to exert a direct pressure upon its forward face.

16 represents a replenishing valve opening inward under external atmospheric pressure and replacing air, which escapes through the pat-kings, whenever, after forward movement of the compressing piston, the pressure of the hamber or reservoir 9 is sufficiently reduced to enable atmosphere to overcome the spring of the valve 16.

The port 14 is located at such a point that it is not uncovered by the piston 4 in moving to its rearward limit and hence the driving pressure for developing the percussion- 1n the piston 6 cannot enter the supply passage 13 and balance ,he driving pressure;,

nor can the front air :ushion be lost at end" of the working stroke by escape of airfrom in fr nt of the too] piston after the port 12 has been mvered.

According to the modification shown in Fig. 4. he reservoir 9 is entirely distinct from the return passage 9 with the result that much higher initial compression will be developed and delivered to'the tool piston, during the covering of theby'pass 10 and the port 11, will reduce the pressure in the chamber 9 to such an extent as to draw in atmosphere on every stroke, if desired, 'under such conditions as may be predetermined by regulation of tension. on the closing spring of the valve 16.

Having thus des'cribedmy invention, what I claim as new therein and desire to secure by Letters Patent is 1. A fluid driven tool of substantially the character described, comp-rising a compressing piston, a pressure driven piston and suitable housing for said pistons in which the compressing piston compresses a charge of air and exerts retracting influence upon the pressure driven piston; said housing having a reservoir, a port between said -reservoir and the part of the housing where the air is compressed; a second port between the reservoir and the space between the pistons by means of which two ports and said reservoir the charge ofcompressed air is conveyed into the space between the pistons and permitted to there act expansively when retraction has taken place, an outlet valve leading to said reservoir from the front part of said housing and a similarly arranged valve close behind the driven piston in its foremost position, said two valves adapted to permit escape of air in advance .of the pistons on their forward strokes, and a port in the forward end of said housing adapted to admit air in front of the pressure driven piston on its rearward stroke; and an air passage establishing communication from the compressing space of the compressing piston to said air admitting port in advance of the pressure driven piston, whereby some of the air compressed by the compressing piston is'utilized to drive the pressure driven piston rearward. v

2. A fluid driven tool of substantially the character described comprising a compressing piston, a pressure driven piston and sui able housing in which said pistons work, confining air in driving relation to the driven piston and providing by its rear-portion a compression chamber in which a charge of 7 ooaaoa the front end to the rear portion of the housing for supplying compressed air to the space in advance of the driven piston when the compressing piston recedes.

' 3. A fluid driven tool of substantially the character described comprising a compressing piston, a pressure driven piston and suit+ able housing in which said pistons work, confining air in driving relation to the driven piston and providing by its rear portion a compression chamber in which a charge of-air is compressed by the compressing piston; said housing having a reservoir and ports connecting the interior of said housing with said reservoirs and adapted respectively to releaseair in advance of the pistons on their forward stroke, and to re lease acharge of compressed air from said reservoir to the space between the pistons when in their retracted position, and a replenishing valve in said reservoir; said housing also havin a port connecting said compression chain er with said reservoir and furthermore a by-pass with a port at each end extending from the front end to the rear portion of the housing, for supplying com-: pressed air to the space in advance of thedriven piston when the compressing piston recedes, one of said by-pass ports bein located in the compression chamber-and a apted to be closed by said compressing piston after commencement of the compressing stroke, whereby retracting pressure is supplied'during but a portion of the compression stroke.

4. A fluid driven tool of substantially the character described comprising a compressing piston, apressure driven piston and suitable housing in which said pistons work, confining air in' driving relation to the driven piston and providing by its rear portion a compressing chamber in which a charge of air is compressed by the compressing piston; said housin having a reservoir, ports connecting the interior of said housing Withsaid reservoir and adapted to release air in advance of the pistons on their forward strokes, and other intercommunicating ports adapted to supply air from said compressing chamber .in advance of the driven piston when at its forward. limit; one of said'intercommunicating ports being controlled by the compressing piston and located in the compression chamber and adapted to be closed by the compressing piston after commencement of the compressing stroke, whereby retracting pressure is supplied during but a portion of compression stroke and said last'named port remaining closed until after the forward stroke of the driven piston, and trapping air in advance of the driven piston'to cushion the latter; said housing also having a port releasing the Will charge of compressed airfrom said reservoir to the space between the pistons when retracted, and also having a port in the compression chamber and in communication with said reservoir.

5. A fluid driven tool of substantially'the' character described, comprising 'a compressing piston, a pressure driven piston, and suitable housing for said pistons in which the compressing piston compresses a charge of air and exerts retracting influence upon the pressure driven piston; said housing having a reservoir, a port between said reservoir and the part of the housing where the air is compressed, a second port between the reservoir and'the space between the pistons, by means of which two said ports and said reservoir the charge of compressed air is conveyed into the space between the pistons and permitted to there act expansively when retraction has taken place, an outlet valve leading to said reservoir from-the front part of said housin and a similarly arranged valve close behind the driven piston in its forward position, said two valves adapted to'perniit escape of air in advance of the pistonson their forward strokes, and a port in the-forward end of said housing adapted v to admit air in-front of the pressure driven piston on its rearward stroke; and an air passage establishing communication from the compressing space of the compressing piston 'tosaid air admitting port in advance of the pressure driven piston, whereby some of the air compressed by the compressing piston is utilized to drive the pressure driven piston rearward, said reservoir receiving air displaced on the forward stroke of the compressing piston, communication with the compression chamber and said reservoir be ing established when air is being supplied from said compression chamber to the space in front of the driven piston.

6. A fluid driven tool of substantially the character described, comprising a compressing piston, a pressure driven piston, and suitable housing for said pistons in which thejcompressing piston compresses a charge of air. and exerts retracting influence upon the pressure driven piston; said housing having a reservoir, a port between said reservoir and the part of the housing where the air is compressed, a second port between the reservoir and the space between the pistons, by means of which two said ports and said'reservoir the charge of compressed air is conveyed into the space between the pistons and permitted to'there act expansively when retraction has taken place, an outlet valve leading to said reservoir from the front part of said housing and a similarly arranged valve close behind the driven piston in its forward position, said two valves adapted to permit escape of air in advance of the pistons on their forward strokes, and a port in the forward end of said housing adapted to admit air in front of the pressure driven piston on its rearward stroke; said second valve constituting a back-flowchecked passage communicating from the space which lies in rear of the driven piston after its forward'stroke to the compression space of the compressing piston, whereby air displaced from between the pistons, by the forward stroke of-the compressing plston, is again delivered for compression.

7 A fluid driven tool of substantially the character described comprising a compressing piston, a pressure drivenpiston and suitable housing in which said pistons work, an air storagereservoir and a by pass, said reservoir and by-pass in cooperation with said housing and compressing piston confining air indriving relation to both sides of the driven piston, said housing providing, by its rear portion, a compression chamber in which a charge of air is compressed by the compressing piston; said housing having an escape port into said reservoir for the air displaced by the forward stroke of the compressing piston and a second port into said reservoir and a third port from said reservoir releasingthe charge of compressed air by means, of said second and third ports and the reservoir to the space betweenthe pistons when retracted; a check valve communicating between the foremost end of said housing and said reservoir for displacing air into the reservoir by the forward stroke of said driven piston, said air storage reservoir having back-fiowchecked communication with said escape port, whereby air in the storage reservoir is subjected to compression.

8. A fluid driven tool of substantially the character described comprising a compressing piston, a pressure driven piston and suitable housing in which said pistons work, an air storage reservoir and a by pass, said reservoir and by pass in cooperation with said housing and compressing piston confining air in driving relation to both sides of the driven piston, said housing providing, by its rear portion, a compression chamber in which a charge of air is compressed by the compressing piston; said housing having an escape port into said reservoir for the air displaced by the forward stroke of the compressing piston and a second port into said reservoir and a third port from said reservoir releasing the charge of compressed air by means of said second and third ports and said reservoir to the space between the pistons when retracted; a check valve communicating between the foremost end of said housing and said reservoir for displacing air into the reservoir by the forward stroke of said driven piston said air storage reservoir having back-flow-checked communication, through which it receives air displaced by the forward stroke of the compressing piston and having communication with the compression chamber through which its contained air is subjected to compression, and also with the port that releases air to the space lying between the pistons when they are retracted.

9. A fluid driven tool of substantially the character described comprising a compressing piston, a pressuredriven piston and a housing for said pistons, a reservoir and a plurality of .ports connecting said housing and said reservoir, and a by pass with other ports therefor situated to connect the foremost portion of said housing with an interpiston portion thereof, said reservoir and bypassin cooperation with said housing, said ports and compressing piston constructed to confine air in driving relation to both sides of the pressure driven piston and in compressing relation to the rear side of the compressing piston; said ports which admit air displaced by the forward strokes of both the pistons. to the reservoir being back-flowchecked and the remainder of said ports between the reservoir and the housing being open both ways.

1.0. A fluid driven tool comprising a compressing piston, a pressure driven piston, a suitable housing, a reservoir, a port between said reservoir and the part of the housing. where the air is compressed; a second port between the ,reservoir and the space between the pistons by means of which two ports and said reservoir the charge of compressed air is conveyed into confining air in driving relation to the rear of the driven piston and in compressing relation to the rear side of the compressing piston, a port in the housing constructed to admit air at the forward end of the housing on the retraction of the driven piston and ports to permit escape of air on the forward strokes of the two pistons into said reservoir, one of said escape ports being situated at the foremostend of said housing to displace air in front of the driven piston and a port to admit compressed air from said reservoir to the space between the pistons when re tracted; said reservoir being provided with a passage in communication with the compression space of the housing, whereby air is not only stored under pressure, but is sup plied to fill the space behind the compress ing piston on the forward stroke of the latter. v

11. A fluid driven tool comprising a cylinder, a tool piston working in said cylinder, a compressing piston working in said cylin der in retractive relation to the tool piston,

a lurality of ports communicating with the 1 cy inder, to wit, an air transmitting port at the front end; back-flow-checked air es cape ports located respectively in front and rear of the tool piston, when near the front end of the cylinder; a compressed air releasing port, at a point between the pistons when retracted; and a port at a point in the rear end of the compression space; and there being a laterally disposed passageway communicating with all of said ports and a by pass with a port, connecting said air transmitting port with the space between the pistons when said compressing piston is in its 10 rearmost position. The foregoin Syracuse New uary, 1910.

specification signed at ork, this 20th day of J an 

